JP4998311B2 - Policer device and bandwidth control program - Google Patents

Description

  The present invention relates to a policer device and a bandwidth control program, and in particular, a policer device and a bandwidth control program capable of allowing a frame to pass evenly even when the supply timing of resources consumed for passing the frame is independent for each policer. About.

  In recent years, for example, in a relay device such as a layer 2 switch (hereinafter referred to as “L2 switch”), QoS (Quality of Service) control for controlling the priority of frame relay according to the quality required for the relayed frame is performed. There is. Such a relay apparatus may be provided with a policer that performs policing on the input side and a shaper that performs shaping on the output side, as described in Patent Document 1, for example.

  FIG. 9 is a block diagram illustrating a schematic configuration of a general L2 switch including a policer and a shaper. The L2 switch shown in the figure includes n ports (n is an integer equal to or greater than 2), classifying units 10-1 to 10-n, policers 20-1 to 20-n corresponding to the respective ports, And shapers 40-1 to 40-n.

  Input frames input from each port of the L2 switch are assigned to classes according to priority by the classifying units 10-1 to 10-n and output to the policers 20-1 to 20-n. Then, the frame is band-controlled by the policers 20-1 to 20-n and output to the switch unit 30. At this time, resources for bandwidth control, generally called tokens, are supplied to the policers 20-1 to 20-n at a predetermined period, and each of the policers 20-1 to 20-n consumes this resource. However, band control according to the class of the frame is performed by outputting the frame within the range of the accumulated resources.

  The frames output from the policers 20-1 to 20-n are output by the switch unit 30 to the shapers 40-1 to 40-n corresponding to the ports corresponding to the destinations of the frames, and the shapers 40-1 to 40-n are output. Is output as an output frame from each port.

JP 2006-173726 A

  By the way, normally, a plurality of policers provided in the relay apparatus are supplied with resources for bandwidth control at independent periods. That is, for example, in the L2 switch shown in FIG. 9, resources are supplied to the policers 20-1 to 20-n at different timings. In addition, when a frame is output from one of the policers, resources in other policers are also consumed. Therefore, depending on the difference in resource supply timing, only some policers always pass the frame. There is.

  Specifically, for example, in FIG. 9, when the resource supply timing for the policer 20-1 is earlier than the resource supply timing for the other policers 20-2 to 20-n, the policer 20-1 The resource is monopolized before the resource supply timing for 20-n. If the policer 20-1 consumes a large amount of resources while monopolizing resources, the resource amount in the policers 20-2 to 20-n is less than 0 before the resource supply timing to the policers 20-2 to 20-n. Even if the resource is supplied at the resource supply timing, the policer 20-2 to 20-n cannot pass the frame unless the resource amount in the policer 20-2 to 20-n is recovered to 0 or more. .

  Thereafter, when the next resource supply timing for the policer 20-1 arrives, the policer 20-1 again monopolizes the resources and passes the frame, and the resources that can be consumed by the other policers 20-2 to 20-n are depleted. End up. Then, due to the resource depletion, the policers 20-2 to 20-n are forced to discard the frames, while the policers 20-1 monopolize the resources and pass new frames one after another. .

  Thus, since the resource supply timing for each policer is independent, the fairness is not guaranteed for the passage of frames, and even if the user who transmits the frame pays the same fee to the communication service provider However, the same band may not be secured in the relay device.

  The present invention has been made in view of the above points, and a policer device and a bandwidth control program capable of allowing a frame to pass evenly even when the supply timing of resources consumed for passing the frame is independent for each policer. The purpose is to provide.

  In order to solve the above-described problem, the policer device according to the present invention includes passage information indicating whether or not each of the own device and the other policer device has passed a frame in each period between resource supply timings unique to the own device. Storage means for storing, management means for managing changes in the amount of resources consumed when the own apparatus or another policer apparatus passes frames, passage information stored by the storage means, and the management means A determination means for determining whether or not to allow the passage of a frame of the own policer in the next cycle after the next resource supply timing based on at least one of the changes in the resource accumulation amount managed by Output means for outputting a frame input to the own device in each cycle between resource supply timings according to the determination; A configuration with.

  According to this configuration, for each period between resource supply timings, it is determined whether or not to allow the policer to pass the frame in the next period based on a change in the amount of accumulated resources or currency information. A policer that has consumed resources by passing a frame can yield resources to another policer in the next period. As a result, even when the supply timing of resources consumed for frame passing is independent for each policer, the frame can be passed through fairly.

  In the policer device according to the present invention, in the above configuration, the determination unit determines that the frame of the own device is not allowed in the next cycle when a frame is output by the output unit during the current cycle including the present time. The structure to do is taken.

  According to this configuration, the policer that has passed the frame during the current cycle determines that the frame of the own policer is not allowed in the next cycle. Policers can give resources to other policers.

  In the policer device according to the present invention, in the configuration described above, the determination unit causes the passage information stored in the storage unit to pass all frames during a predetermined number of cycles before the current cycle. In this case, even if a frame is output by the output means during the current period, a configuration is adopted in which it is determined that the frame passing of the own apparatus is permitted in the next period.

  According to this configuration, if all policers have passed a frame by the current cycle, the frame of the own policer is permitted in the next cycle regardless of whether or not the frame has been passed during the current cycle. For this reason, if all policers have already passed the frame fairly, the own policer will not stop passing the frame unnecessarily.

  In the policer apparatus according to the present invention, in the configuration described above, the determination unit determines that the current period is less than 0 when the resource accumulation amount managed by the management unit is 0 or more at the end of the previous period before the previous resource supply timing. Even if a frame is output by the output means, a configuration is adopted in which it is determined that the frame of the own apparatus is allowed in the next period.

  According to this configuration, if resources remain at the end of the previous period, the frame of the own policer is permitted in the next period regardless of whether or not the frame is passed during the current period. For this reason, when a frame to be passed through is not input to another policer in the first place, it is possible to allow the own policer to pass through the frame and to prevent a band break.

  In the policer apparatus according to the present invention, in the configuration described above, the determining means passes only the same policer apparatus whose passage information stored in the storage means is the same in a predetermined number of consecutive periods before the current period. In the case of indicating that it has been done, a configuration is adopted in which it is determined that the frame passing of the own apparatus is permitted in the next period.

  According to this configuration, when only the same policer passes a frame in a predetermined number of consecutive cycles, it is determined that the own policer is allowed to pass the frame in the next cycle. For this reason, each policer determines that the policer that has passed the frames in successive cycles is actually a policer in use, and prevents resources from being unnecessarily yielded to other unused policers. be able to.

  In the policer device according to the present invention, in the configuration described above, the determining unit may perform the following operation when the resource accumulation amount managed by the managing unit is 0 or less at the beginning of the current cycle after the previous resource supply timing. A configuration is adopted in which whether or not the device passes the frame in the cycle is equivalent to the current cycle.

  According to this configuration, if there is a shortage of resources at the beginning of the current cycle, whether to pass frames in the next cycle is not changed from the current cycle. For this reason, for example, if a large frame passes through any policer in the previous period and many resources are consumed, the current status can be maintained until the accumulated amount of resources recovers to 0 or more. Can ensure fairness.

  In the policer device according to the present invention, in the above configuration, the management unit subtracts the consumed resource amount consumed by passing the frame from the resource accumulation amount when the own device or another policer device passes the frame. Take the configuration.

  According to this configuration, since the resource amount corresponding to the frame passing by the own policer or another policer is subtracted from the resource accumulation amount of the own policer, the frame can be passed within the range of resources supplied to the own policer. The upper limit of the amount of resources to be consumed can be strictly observed.

  In the policer apparatus according to the present invention, in the configuration described above, the management unit may be configured such that when the sum of the current resource accumulation amount and the constant resource amount supplied at the resource supply timing is 0 or less, Even if the frame is passed, a configuration is adopted in which the consumed resource amount is not subtracted from the resource accumulation amount.

  According to this configuration, if the sum of the current resource accumulation amount and the supplied resource amount is 0 or less, the consumed resource amount is not subtracted from the resource accumulation amount. For this reason, even if another policer having a clock frequency that is fast and out of synchronization with the period of one or more cycles passes through the frame, the resource accumulation amount of the own policer does not decrease, and the clock frequency does not decrease. Early policers can be prevented from monopolizing resources.

  In the policer apparatus according to the present invention, in the configuration described above, the determination unit includes a resource surplus flag indicating whether or not the resource accumulation amount is 0 or more before the resource supply timing, and the resource accumulation amount is 0 after the resource supply timing. By updating a flag stored by the storage unit, including a flag storage unit that stores a supply sufficiency flag that indicates whether or not the above is satisfied and a skip flag that indicates whether or not to allow frame passage of the own device. In the next cycle, a configuration is adopted in which it is determined whether or not to allow the own device to pass through the frame.

  According to this configuration, by updating the resource surplus flag, the supply sufficiency flag, and the skip flag, it is determined whether or not the own policer is allowed to pass through the frame. be able to.

  The bandwidth control program according to the present invention is a bandwidth control program that is executed by a computer having a plurality of policers. The bandwidth control program according to the present invention includes a first control program for each period between resource supply timings unique to the first policer. A first acquisition step of acquiring passage information indicating whether or not each of the policer and the second policer has passed the frame; and resources consumed when the first policer or the second policer passes the frame. Based on the second acquisition step for acquiring the change in the storage amount, the passage information acquired in the first acquisition step, or the change in the resource storage amount acquired in the second acquisition step, the next resource supply timing A decision step for deciding whether or not to allow the first policer to pass through a frame in a subsequent next period; As determined in-up was a frame input to the first policer so as to execute an output step of outputting in the next period between resource supply timing.

  The bandwidth control method according to the present invention is a bandwidth control method in a policer device provided in the same device together with other policer devices, and in each period between resource supply timings specific to the own policer device, A first acquisition step of acquiring passage information indicating whether or not each of the other policer devices has passed the frame; and a storage amount of resources consumed when the own policer device or another policer device passes the frame. Based on the second acquisition step of acquiring a change and the passage information acquired in the first acquisition step or the change in the resource accumulation amount acquired in the second acquisition step, the next after the next resource supply timing A determination step for determining whether or not to allow frame passage of the own policer device in a period; and According constant, and to an output step of outputting the frame input to the own policer device in the next period between resource supply timing.

  According to these, in order to determine whether to allow the passage of the own policer frame in the next cycle based on the change in the amount of accumulated resources or the currency information for each cycle between resource supply timings, When a policer passes a frame and consumes resources, the resource can be transferred to another policer in the next period. As a result, even when the supply timing of resources consumed for frame passing is independent for each policer, the frame can be passed through fairly.

  According to the policer device and the bandwidth control program disclosed in the present specification, even when the supply timing of resources consumed for frame passing is independent for each policer, it is possible to pass frames fairly.

  The gist of the present invention is that a policer that has passed a frame refrains from consuming resources after the next resource supply timing, and yields resources to another policer. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an L2 switch according to an embodiment of the present invention. The L2 switch shown in the figure includes classifying units 100-1 to 100-n, policers 200-1 to 200-n, a switch unit 300, and shapers 400-1 to 400-n.

  The classifying units 100-1 to 100-n are connected to different ports, respectively, and receive frames input from the ports. Then, the classification units 100-1 to 100-n allocate the frames to classes according to the priorities, and output the classes to the policers 200-1 to 200-n, respectively.

  The policers 200-1 to 200-n pass the frames while performing bandwidth control while consuming resources supplied at independent resource supply timings. The policers 200-1 to 200-n discard the frames output from the classifying units 100-1 to 100-n when the resources necessary to pass the frames are exhausted. In addition, when the resource supply timing arrives, the policers 200-1 to 200-n update the skip flag indicating whether or not to pass the frame until the next resource supply timing, and the updated skip flag is updated. It is determined with reference to whether or not to pass the frame. At this time, the policers 200-1 to 200-n obtain passing information indicating whether or not the own policer and other policers have passed the frame from the switch unit 300, and skip so that each policer passes the frame fairly. Update the flag. The configuration and operation of policers 200-1 to 200-n will be described in detail later.

  The switch unit 300 outputs the frame to the shapers 400-1 to 400-n connected to the ports corresponding to the destination address of the frame. And the switch part 300 outputs the passage information which can identify the policers 200-1 to 200-n through which the outputted frame is passed to each of the policers 200-1 to 200-n.

  The shapers 400-1 to 400-n are connected to different ports, respectively, and output the frames output from the switch unit 300 via the respective ports while performing band control. At this time, the shapers 400-1 to 400-n output all the frames from the ports while queuing and delaying the frames as necessary so as not to exceed a predetermined band. That is, the shapers 400-1 to 400-n do not discard the frame.

  FIG. 2 is a block diagram showing a main configuration of policer 200 according to the present embodiment. The policer 200 shown in the figure includes a frame input / output unit 201, a passage information acquisition unit 202, a resource management unit 203, a management information storage unit 204, a flag update unit 205, and a flag determination unit 206. Note that policers 200-1 to 200-n shown in FIG. 1 have the same configuration as policer 200 shown in FIG.

  The frame input / output unit 201 passes the frame output from the corresponding classification unit according to the instruction of the flag determination unit 206 while consuming the resource managed by the resource management unit 203. In other words, the frame input / output unit 201 allows the frame to pass if the resource accumulation amount managed by the resource management unit 203 is greater than 0 and the flag determination unit 206 permits the passage of the frame. Note that the amount of resources consumed by the frame input / output unit 201 for passing a frame varies depending on the size of the frame. If the frame is large, the amount of resource consumed is large, and if the frame is small, the amount of resource consumed is small.

  Each time the switch unit 300 outputs a frame, the passage information acquisition unit 202 acquires passage information indicating the size of the frame and a policer that has passed the frame from the switch unit 300. Then, the passage information acquisition unit 202 refers to the acquired passage information, notifies the resource management unit 203 of the frame size, and notifies the management information storage unit 204 of the policer that has passed the frame.

  The resource management unit 203 manages the amount of resources supplied and consumed in the policer 200. That is, when a resource is supplied at a resource supply timing specific to the policer 200, the resource management unit 203 increases the resource accumulation amount in the policer 200 by the supplied resource amount, and the policer 200 or another policer passes the frame. Then, the resource accumulation amount in the policer 200 is reduced by the consumed resource amount.

  Specifically, the resource management unit 203 manages the resource accumulation amount that fluctuates as shown in FIG. 3, for example. That is, since the resource supply timing for the policer 200 arrives at a predetermined cycle, if the cycle between the resource supply timings is set to the previous cycle, the current cycle, and the next cycle in time series, the resource storage managed by the resource management unit 203 is stored. The amount increases by a constant PIR (Peak Information Rate) at the resource supply timing at the boundary of each cycle. Further, during each period, the policer 200 or another policer passes the frame, so that the resource accumulation amount managed by the resource management unit 203 gradually decreases.

  The management information storage unit 204 stores management information including flag information such as passage information indicating a policer that has passed a frame during each period and a skip flag. Specifically, as shown in FIG. 4, for example, the management information storage unit 204 includes passage information, skip flags, resources indicating whether all policers including the own policer 200 have passed frames in the current cycle and the previous cycle. It has a management information table for storing surplus flags and supply sufficiency flags. This management information table stores not only current passage information and flag information but also past passage information and flag information.

  In FIG. 4, the current cycle passage information and the previous cycle passage information indicate a policer that has passed a frame in the current cycle and the previous cycle by “1”, and a policer that has not passed the frame by “0”. These passage information can be registered when the policer that has passed the frame is notified from the passage information acquisition unit 202 to the management information storage unit 204. The skip flag indicates whether or not the own policer 200 skips resource consumption in the next period. That is, when the own policer 200 skips the consumption of resources for passing frames in the next cycle, the skip flag is set to “1”, and the own policer 200 uses less resources for passing frames in the next cycle. If it is allowed, the skip flag is set to “0”.

  Furthermore, the resource surplus flag indicates whether or not the resources that can be consumed by the own policer 200 are left at the end of the current cycle. That is, when the resource accumulation amount managed by the resource management unit 203 is larger than 0 at the end of this cycle, the resource surplus flag is set to “1”, and the resource accumulation amount managed by the resource management unit 203 is at the end of this cycle. If it is 0 or less, the resource surplus flag is set to “0”. The supply sufficiency flag indicates whether or not there is a resource that can be consumed by the own policer 200 in the next cycle when the resource is supplied at the resource supply timing between the current cycle and the next cycle. That is, when the resource accumulation amount managed by the resource management unit 203 becomes greater than 0 after supplying the resource, the supply satisfaction flag is set to “1”, and the resource accumulation amount managed by the resource management unit 203 is after the resource supply. If the value is also 0 or less, the supply satisfaction flag is set to “0”.

  Based on the resource accumulation amount managed by the resource management unit 203 and the passing information and flag information stored by the management information storage unit 204, the flag update unit 205 stores the skip flag, the resource stored in the management information storage unit 204, The surplus flag and supply sufficiency flag are updated. Specifically, the flag update unit 205 determines whether or not the resource accumulation amount is greater than 0 at the end of each cycle, and newly registers a resource surplus flag at the end of the cycle based on the determination result. Further, the flag update unit 205 determines whether or not the resource accumulation amount has become larger than 0 after the resource is supplied at the end of each cycle, and newly registers a supply satisfaction flag at the end of the cycle based on the determination result.

  Furthermore, the flag update unit 205 determines whether or not the own policer 200 skips resource consumption in the next cycle based on the resource surplus flag and supply sufficiency flag at the end of the previous cycle and the passage information of the previous cycle and the current cycle. A new skip flag is registered. At this time, the flag updating unit 205 has a policer in which the own policer 200 has passed the frame in this cycle and has not passed the frame by this cycle, and there is no remaining resource at the end of the previous cycle. When the resource surplus flag indicates this, the skip flag is set to “1”.

  This is because when the own policer 200 passes a frame in this cycle, there is a possibility that another policer could not pass the frame in this cycle due to resource consumption by the own policer 200. In the next period, it means that the own policer 200 yields resources to another policer. However, if all policers have passed the frame by the current cycle, it is considered that each policer has passed the frame fairly. Therefore, the own policer 200 does not need to yield resources in the next cycle. Also, if there is a surplus of resources at the end of the previous period, it is considered that there are no frames that other policers pass in the first place, even if other policers do not pass frames in this period. Policer 200 does not need to yield resources in the next period.

  In this way, the flag update unit 205 determines whether or not the own policer 200 gives resources to other policers in the next period so that each policer passes the frame fairly. A skip flag “1” is newly registered at the end of this cycle. The flag update processing by the flag update unit 205 will be described in detail later.

  The flag determination unit 206 refers to the latest skip flag stored in the management information storage unit 204. If the skip flag is “0”, the frame input / output unit 201 permits the frame to pass, and the skip flag Is “1”, the frame input / output unit 201 is prohibited from passing the frame.

  Next, the operation at the resource supply timing of the policer 200 configured as described above will be described with reference to the flowchart shown in FIG. In the following, a bandwidth control method for controlling the bandwidth in the next cycle by updating the flag at the resource supply timing at the boundary between the current cycle and the next cycle will be described.

  While the own policer 200 or another policer passes the frame, the passage information acquisition unit 202 acquires the passage information, and the resource accumulation amount in the resource management unit 203 and the current period passage information in the management information storage unit 204 are registered. Is done. When the resource supply timing of the policer 200 comes and this cycle is completed (step S101), the flag update unit 205 executes a skip flag update process (step S102).

  The skip flag update processing is performed based on the passage information of the previous cycle and the current cycle, the resource surplus flag at the end of the previous cycle, and the supply sufficiency flag at the end of the previous cycle (that is, the beginning of the current cycle). This skip flag update process will be described in detail later.

  Then, the flag update unit 205 executes resource surplus flag update processing according to whether or not the resource accumulation amount in the resource management unit 203 remains at the end of the current cycle (step S103). This resource surplus flag update processing will also be described in detail later.

  When the skip flag and resource surplus flag stored in the management information storage unit 204 are updated, resources are supplied to the own policer 200 by a certain PIR (step S104), and the resource accumulation amount stored in the resource management unit 203 is Increase by PIR. Then, the flag update unit 205 determines whether or not the resource accumulation amount after the resource supply is greater than 0 (step S105). If the resource accumulation amount is greater than 0 (step S105 Yes), the management information storage unit A supply satisfaction flag “1” is newly registered in 204 (step S106), and if the resource accumulation amount is 0 or less (No in step S105), a supply satisfaction flag “0” is newly registered in the management information storage unit 204. (Step S107).

  In this way, when the resource supply and flag update at the end of the current cycle are completed, the next cycle is started (step S108). During the next cycle, the flag determination unit 206 refers to the latest skip flag, and the skip flag is set. If it is “0”, the frame input / output unit 201 passes the frame while consuming the resource accumulation amount of the resource management unit 203. On the other hand, if the skip flag is “1”, the resource is transferred to another policer, and the own policer 200 does not pass the frame.

  Next, skip flag update processing according to the present embodiment will be described with reference to the flowchart shown in FIG. The flag update unit 205 executes the skip flag update process shown in FIG.

  First, the flag update unit 205 refers to the latest current cycle passage information stored in the management information storage unit 204, and determines whether or not the own policer 200 has passed the frame during this cycle (step S201). . As a result, when the own policer 200 passes the frame during the current cycle (Yes in step S201), it may be fair that the own policer 200 yields resources to another policer in the next cycle.

  Therefore, the flag update unit 205 refers to the current period passage information and the previous period passage information, and determines whether all other policers have passed the frame by the present period (step S202). As a result, if all the other policers have passed the frame by this cycle (Yes in step S202), it is considered that all the policers have passed the frame fairly. There is no need to give resources to the policer, and a skip flag “0” is newly registered in the management information storage unit 204 (step S206). If there is another policer that has not passed the frame by this cycle (No in step S202), there may be a policer that has not been able to pass the frame by this cycle due to resource depletion.

  Therefore, the flag update unit 205 refers to the resource surplus flag at the end of the previous cycle, and determines whether there is a surplus of resources at the end of the previous cycle (that is, whether the resource surplus flag is “1”). (Step S203). As a result, if there are remaining resources at the end of the previous cycle (Yes in step S203), it is considered that no frame has been input to the policer that has not passed the frame until the current cycle, so In step S206, it is not necessary to transfer resources to another policer, and a skip flag “0” is newly registered in the management information storage unit 204 (step S206). Also, if there are no remaining resources at the end of the previous cycle (No in step S203), it is considered that there is a policer that has not been able to pass the frame by the current cycle due to resource depletion, so skip to the management information storage unit 204. A flag “1” is newly registered (step S204).

  On the other hand, when the own policer 200 does not pass the frame during the current cycle (No in step S201), the flag update unit 205 refers to the current cycle passage information and the previous cycle passage information, and all the policers including the own policer 200 It is determined whether or not the frame has been passed by this cycle (step S205). As a result, if all the policers have passed the frame by the current cycle (step S205 Yes), it is considered that all the policers have passed the frame fairly. There is no need to transfer resources to the management information storage unit 204, and a skip flag “0” is newly registered (step S206). Further, if all policers have not passed frames by the present cycle (No in step S205), there may be policers that have not been able to pass frames by the present cycle due to resource depletion.

  Here, since there is a possibility that the policer that could not pass the frame is the own policer 200, the skip flag “1” is not newly registered in the management information storage unit 204. However, the flag update unit 205 determines whether or not the supply satisfaction flag at the end of the previous cycle (that is, the beginning of the current cycle) is “1” (step S207), and the supply satisfaction flag is “0”. (No in step S207), the same skip flag as the previous time is registered in the management information storage unit 204 (step S210).

  Here, the supply satisfaction flag at the end of the previous cycle (the beginning of the current cycle) is “0” means that a huge frame that consumes many resources in the previous cycle has passed through any policer. This indicates that even if resources are supplied at the resource supply timing, the resource accumulation amount has not recovered to a value greater than zero. Therefore, in such a case, neither policer changes the skip flag and maintains the current state. Then, when the resource accumulation amount recovers to a value larger than 0, the skip flag is properly updated again.

  If the supply satisfaction flag at the end of the previous cycle (the beginning of the current cycle) is “1” (Yes in step S207), the flag update unit 205 refers to the latest current cycle passage information and the previous cycle passage information, It is determined whether or not the policer that has passed the frame in the current cycle matches the previous cycle (step S208). As a result, if the same policer passes the frame in the current cycle and the previous cycle (step S208 Yes), since the supply of resources is sufficient, only the policer that passed the frame in the current cycle and the previous cycle It is considered that policers are in use and the remaining policers are unused policers. Here, since the own policer 200 does not pass the frame in the current cycle, the own policer 200 is a policer that is not used because the frame is not passed in the current cycle and the previous cycle. Since it is not necessary to consider the fairness of resource consumption for an unused policer, a skip flag “0” is newly registered in the management information storage unit 204 (step S206).

  On the other hand, if the policer that passes the frame is different between the current cycle and the previous cycle (step S208 No), the flag update unit 205 refers to the resource surplus flag at the end of the previous cycle, and there is a surplus of resources at the end of the previous cycle. (Ie, whether the resource surplus flag is “1”) is determined (step S209). As a result, if there are surplus resources at the end of the previous cycle (Yes in step S209), it is considered that no frame has been input to the policer that has not passed the frame until the present cycle, so In step S206, it is not necessary to transfer resources to another policer, and a skip flag “0” is newly registered in the management information storage unit 204 (step S206).

  Also, if there is no resource remaining at the end of the previous cycle (No in step S209), it is considered that the overall resource consumption is large and the supply of resources is sufficient, but not all policers pass the frame sufficiently. Therefore, the same skip flag as the previous time is registered in the management information storage unit 204 (step S210). That is, in this case, although the skip flag in the own policer 200 has been changed in the past, it is considered that the fairness of frame passing has not been sufficiently ensured, so that the own policer 200 maintains the current state. I have to.

  As described above, when there is a possibility that the own policer 200 consumes resources in this cycle and another policer cannot consume resources in this cycle, the skip flag is changed to “1”. In the period, the own policer 200 refrains from consuming resources, and other policers can consume resources instead. As a result, fairness of resource consumption by a plurality of policers can be ensured.

  Next, the resource surplus flag update processing according to the present embodiment will be described with reference to the flowchart shown in FIG. The resource surplus flag update process shown in the figure is executed by the flag update unit 205 when the resource supply timing comes.

  First, the flag update unit 205 refers to the latest current cycle passage information stored in the management information storage unit 204, and determines whether or not the own policer 200 has passed the frame during this cycle (step S301). . As a result, if the own policer 200 does not pass the frame during this period (No in step S301), it is considered that the own policer 200 could not pass the frame due to the exhaustion of resources, so there are not enough resources. The resource surplus flag “0” is newly registered in the management information storage unit 204 (step S302).

  On the other hand, when the own policer 200 passes the frame during the current cycle (Yes in step S301), the flag update unit 205 refers to the latest current cycle passage information, and all other policers pass the frame during the current cycle. It is determined whether or not it has been passed (step S303). As a result, if all other policers have passed the frame during this cycle (step S303 Yes), all the policers including the own policer 200 have passed the frame during this cycle, and the amount of resources is reduced. Since it is considered sufficient, it is considered that it is not necessary for any policer to yield resources to another policer in the next period. Therefore, the resource surplus flag “0” is newly registered in the management information storage unit 204 (step S302), so that the update of the skip flag at the end of the next cycle is not affected.

  If there is another policer that has not passed the frame in the current cycle (No in step S303), it is determined whether or not the resource accumulation amount managed by the resource management unit 203 is greater than 0 (step S304). . As a result, if the amount of accumulated resources is 0 or less (No in step S304), there is no remaining resource at the end of the current cycle, so a resource surplus flag “0” is newly registered in the management information storage unit 204 ( Step S302). If the resource accumulation amount is greater than 0 (Yes in step S304), the resource is left at the end of the current cycle, so that the resource surplus flag “1” is newly registered in the management information storage unit 204 (step S305). ).

  In this way, when the own policer 200 passes the frame in this cycle and a part of other policers passes the frame, and the resource accumulation amount is larger than 0 at the end of this cycle, the resource surplus flag is set. Since it is changed to “1”, when the own policer 200 updates the skip flag at the end of the next cycle, it is possible to accurately determine whether or not to give resources to another policer.

  As described above, according to the present embodiment, the own policer has passed the frame in this cycle, while the other policers have not passed the frame, and further, there is no remaining resource at the end of the previous cycle. In this case, the own policer updates the skip flag to “1” at the resource supply timing at the end of the current cycle, and transfers the resource to another policer in the next cycle. For this reason, even if the resource that the policer can consume in the next cycle is supplied at the resource supply timing, the policer does not monopolize the resource in the next cycle. By executing the same processing for other policers, even if the supply timing of resources consumed for frame passing is independent for each policer, it is possible to pass frames fairly.

  By the way, when the own policer or another policer passes the frame in each cycle, the own policer subtracts the consumed resource amount from the resource accumulation amount managed by the resource management unit 203. At this time, if the clock frequency that determines the period in each policer is shifted, the clock frequency shift accumulates in the long term, resulting in a synchronization loss of one period or more, and a policer with a fast clock frequency advantageously passes through the frame. Will end up. Therefore, the resource management unit 203 needs to consider that there is no resource consumption by ignoring frame passing by a policer having a fast clock frequency and shifted by one or more periods from the own policer.

  Therefore, the resource management unit 203 reflects the resource consumption during the period in the resource accumulation amount of the own policer 200 according to the flowchart shown in FIG. That is, the resource management unit 203 determines whether or not the own policer 200 has passed the frame (step S401). As a result, if the own policer 200 passes the frame (Yes in step S401), the resource amount consumed for passing the frame is subtracted from the resource accumulation amount (step S402).

  On the other hand, if a policer other than the own policer 200 passes the frame (No in step S401), whether the value obtained by adding the PIR supplied at the next resource supply timing to the current resource accumulation amount is 0 or less. Is determined (step S403). In other words, at the next resource supply timing, it is determined whether or not the resource accumulation amount of the own policer 200 is scheduled to recover to a value larger than zero.

  As a result, if the amount of accumulated resources is 0 or less even after adding PIR (Yes in step S403), the clock frequency of the other policer that has passed the frame is fast, and the synchronization of the own policer 200 is out of synchronization by one period or more. Therefore, the amount of resources consumed for passing through this frame is not subtracted from the amount of accumulated resources (step S404). Further, if the resource accumulation amount becomes larger than 0 if PIR is added (No in step S403), it is considered that there is no loss of synchronization for one cycle or more. Therefore, the resource amount consumed for passing through this frame is the resource accumulation amount. Is subtracted from (step S402).

  As a result, when the cycle of another policer with a fast clock frequency is shifted by one cycle or more from the cycle of the own policer 200, the frame passing by the other policer does not affect the resource accumulation amount of the own policer 200. As a result, even if the synchronization between the policers is lost due to the shift of the clock frequency of each policer, the specific policer does not advantageously pass the frame, and the fairness can be reliably ensured.

  In the above-described embodiment, the case where the policers 200-1 to 200-n are provided in the L2 switch has been described. However, the present invention is not limited to this, and the band limitation is performed by a plurality of policers. The present invention can be applied in the same manner as in the above embodiment.

  In the above embodiment, the bandwidth control method in policers 200-1 to 200-n has been described. However, this bandwidth control method is described as a computer-readable bandwidth control program, and the bandwidth control program is stored in the computer. By performing this, it is possible to obtain the same operation and effect as the one embodiment.

  Regarding the above embodiment, the following additional notes are disclosed.

(Supplementary Note 1) Storage means for storing passage information indicating whether or not each of the own device and other policer devices has passed a frame in each cycle between resource supply timings specific to the own device;
A management means for managing a change in the amount of accumulated resources consumed when the own device or another policer device passes a frame;
Whether to allow the own policer to pass the frame in the next cycle after the next resource supply timing based on at least one of the passage information stored by the storage unit and the change in the resource accumulation amount managed by the management unit A determination means for determining whether or not;
A policer device comprising: an output unit that outputs a frame input to the own device in each cycle between resource supply timings according to the determination by the determination unit.

(Supplementary note 2)
2. The policer device according to claim 1, wherein when a frame is output by the output means during the current cycle including the present time, it is determined that the frame passing of the own device is not permitted in the next cycle.

(Supplementary note 3)
If the passage information stored by the storage means indicates that all policer devices have passed the frame during a predetermined number of cycles before the current cycle, the frame may be output by the output means during the current cycle. The policer device according to appendix 2, wherein the policer device is determined to allow the frame passing of the device itself in the next cycle.

(Supplementary note 4)
If the accumulated amount of resources managed by the management means at the end of the previous period before the previous resource supply timing is 0 or more, even if a frame is output by the output means during the current period, The policer device according to attachment 2, wherein it is determined that frame passage is allowed.

(Supplementary note 5)
When the passage information stored by the storage means indicates that only the same policer device has passed a frame in a predetermined number of consecutive cycles before the current cycle, it is determined that the own device is allowed to pass the frame in the next cycle. The policer device according to appendix 1, wherein:

(Appendix 6) The determination means includes:
When the accumulated amount of resources managed by the management means at the beginning of the current cycle after the previous resource supply timing is less than or equal to 0, whether or not the device passes the frame in the next cycle is equal to the current cycle The policer apparatus according to appendix 1.

(Appendix 7) The management means includes
2. The policer device according to appendix 1, wherein when the own device or another policer device passes a frame, the consumed resource amount consumed by passing the frame is subtracted from the resource accumulation amount.

(Appendix 8) The management means
When the sum of the current resource accumulation amount and the constant resource amount supplied at the resource supply timing is 0 or less, the consumed resource amount is not subtracted from the resource accumulation amount even if another policer device passes the frame. The policer device according to appendix 7, characterized by:

(Supplementary note 9)
A resource surplus flag indicating whether or not the resource accumulation amount is 0 or more before the resource supply timing, a supply sufficiency flag indicating whether or not the resource accumulation amount is 0 or more after the resource supply timing, and the own device frame passing Flag storage means for storing a skip flag indicating whether or not to allow,
2. The policer device according to appendix 1, wherein the policer device determines whether or not to allow frame passage of the device itself in the next cycle by updating the flag stored by the storage means.

(Supplementary Note 10) A bandwidth control program executed by a computer including a plurality of policers, the computer including:
A first acquisition step of acquiring passage information indicating whether or not each of the first policer and the second policer has passed a frame in each period between resource supply timings specific to the first policer;
A second acquisition step of acquiring a change in an accumulation amount of resources consumed when the first policer or the second policer passes the frame;
Based on the passage information acquired in the first acquisition step or the change in the amount of accumulated resources acquired in the second acquisition step, the first policer passes through the frame in the next cycle after the next resource supply timing. A decision step for deciding whether to allow,
According to the determination in the determination step, a bandwidth control program that executes an output step of outputting a frame input to the first policer in a next period between resource supply timings.

(Supplementary Note 11) A bandwidth control method in a policer device provided in the same device together with other policer devices,
A first acquisition step of acquiring passage information indicating whether or not each of the own policer device and another policer device has passed a frame in each period between resource supply timings specific to the own policer device;
A second acquisition step of acquiring a change in an accumulation amount of resources consumed when the own policer device or another policer device passes a frame;
Based on the passage information acquired in the first acquisition step or the change in the resource accumulation amount acquired in the second acquisition step, the own policer device is allowed to pass the frame in the next cycle after the next resource supply timing. A decision step to decide whether or not to do;
A bandwidth control method comprising: an output step of outputting a frame input to the policer device in a next cycle between resource supply timings according to the determination in the determination step.

  The present invention can be applied to a case where a frame is allowed to pass evenly even when the supply timing of resources consumed for passing the frame is independent for each policer.

It is a block diagram which shows schematic structure of the L2 switch which concerns on one embodiment. It is a block diagram which shows the principal part structure of the policer which concerns on one Embodiment. It is a figure which shows an example of the fluctuation | variation of the resource accumulation amount which concerns on one Embodiment. It is a figure which shows an example of the management information table which concerns on one Embodiment. It is a flowchart which shows the operation | movement in the resource supply timing of the policer which concerns on one Embodiment. It is a flowchart which shows the skip flag update process which concerns on one Embodiment. It is a flowchart which shows the resource surplus flag update process which concerns on one embodiment. It is a flowchart which shows the operation | movement in the resource subtraction timing of the policer which concerns on one embodiment. It is a block diagram which shows schematic structure of a L2 switch.

Explanation of symbols

200-1 to 200 -n, 200 Policer 201 Frame input / output unit 202 Passage information acquisition unit 203 Resource management unit 204 Management information storage unit 205 Flag update unit 206 Flag determination unit

Claims (7)

Storage means for storing passage information indicating whether each of the own device and another policer device has passed a frame in each cycle between resource supply timings unique to the own device;
A management means for managing a change in the amount of accumulated resources consumed when the own device or another policer device passes a frame;
Whether to allow the own policer to pass the frame in the next cycle after the next resource supply timing based on at least one of the passage information stored by the storage unit and the change in the resource accumulation amount managed by the management unit A determination means for determining whether or not;
A policer device comprising: an output unit that outputs a frame input to the own device in a next period between resource supply timings according to the determination by the determination unit. The determining means includes
2. The policer device according to claim 1, wherein when a frame is output by the output means during the current cycle including the present time, the policer device determines that it does not allow the frame to pass through in the next cycle. The determining means includes
If the passage information stored by the storage means indicates that all policer devices have passed a frame during a predetermined number of cycles before the current cycle, even if a frame is output by the output means during the current cycle. 3. The policer apparatus according to claim 2, wherein the policer apparatus determines that the frame of the own apparatus is allowed to pass in the next period. The determining means includes
If the accumulated amount of resources managed by the management means at the end of the previous period before the previous resource supply timing is 0 or more, even if a frame is output by the output means during the current period, 3. The policer device according to claim 2, wherein it is determined that frame passage is allowed. The determining means includes
When the passage information stored by the storage means indicates that only the same policer device has passed a frame in a predetermined number of consecutive cycles before the current cycle, it is determined that the own device is allowed to pass the frame in the next cycle. The policer apparatus according to claim 1, wherein: A bandwidth control program executed by a computer having a plurality of policers, the computer having:
A first acquisition step of acquiring passage information indicating whether or not each of the first policer and the second policer has passed a frame in each period between resource supply timings specific to the first policer;
A second acquisition step of acquiring a change in an accumulation amount of resources consumed when the first policer or the second policer passes the frame;
Based on the passage information acquired in the first acquisition step or the change in the amount of accumulated resources acquired in the second acquisition step, the first policer passes through the frame in the next cycle after the next resource supply timing. A decision step for deciding whether to allow,
According to the determination in the determination step, a bandwidth control program that executes an output step of outputting a frame input to the first policer in a next period between resource supply timings. A bandwidth control method in a policer device provided in the same device together with other policer devices,
A first acquisition step of acquiring passage information indicating whether or not each of the own policer device and another policer device has passed a frame in each period between resource supply timings specific to the own policer device;
A second acquisition step of acquiring a change in an accumulation amount of resources consumed when the own policer device or another policer device passes a frame;
Based on the passage information acquired in the first acquisition step or the change in the resource accumulation amount acquired in the second acquisition step, the own policer device is allowed to pass the frame in the next cycle after the next resource supply timing. A decision step for deciding whether or not to do;
A bandwidth control method comprising: an output step of outputting a frame input to the policer device in a next cycle between resource supply timings according to the determination in the determination step.

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